As a blogger, I don't think about keywords enough. Yet somehow I still sleep at night. But as Josh explains, maximising their use is important for business.
However something I wouldn't recommend is a concept called black hatting; unethical search engine optimisation techniques. This includes the use of hidden keywords or links in order to improve your search engine rank.
Particularly not good if you're a reputable businesses like Endota.
Check out this page on their official website and view the source code. Below is a screenshot because I imagine they'll remove the code in the next few days...